Download or read book Film Cooling Effectiveness on a Flat Plate in High Free stream Turbulence Using a Single Row of 30 x1B p0 x1B s Slant hole Injectors written by Geoffrey W. Jumper (MAJ, USAF.) and published by . This book was released on 1987 with total page 130 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Film Cooling Effectiveness on a Flat Plate in High Free Stream Turbulence Using a Single Row of 30 Deg Slant Hole Injectors written by Geoffrey W. Jumper and published by . This book was released on 1987 with total page 91 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the continuing search to understand the mechanisms influencing film cooling effectiveness, this thesis examines film cooling effectiveness on a flat plate in high free-stream turbulence using a single row of 30 slant-hole injectors. The primary area of focus is the area within 42 diameters down-stream of injection. of interest are blowing rates for optimum film cooling effectiveness within 10 diameters down-stream of injection, and the decay of film cooling effectiveness down the plate. Free-stream velocities from 50-175 fps and free-stream turbulence intensities from 13.5 - 18.5% were examined. Changes in Reynolds number or free-stream turbulence had little effect on blowing rates for optimum film cooling effectiveness. In comparison with tests conducted in low free-stream turbulence, around 5%, higher free-stream turbulence causes a faster decay in film cooling effectiveness down the plate.

Download or read book The Effect of High Freestream Turbulence on Film Cooling Effectiveness written by and published by . This book was released on 1994 with total page 20 pages. Available in PDF, EPUB and Kindle. Book excerpt: This study investigated adiabatic wall cooling effectiveness of a single row of film cooling holes injecting into a turbulent flat plate boundary layer below a turbulent, zero pressure gradient freestream. Levels of freestream turbulence (Tu) up to 17.4% were generated using a method which simulates conditions at a gas turbine combustor exit. Film cooling was injected from a single row of five 35 degree slant-hole injectors (length/diameter = 3.5. pitch/diameter = 3.0) at blowing ratios from 0.55 to 1185 and at a nearly constant density ratio (coolant density/freestream density) of 0.95. Film cooling effectiveness data is presented for Tu levels ranging from 0.9% to 17% at a constant freestream Reynolds number based on injection hole diameter of 19000. Results show that elevated levels of freestream turbulence reduce film cooling effectiveness by up to 70% in the region directly downstream of the injection hole due to enhanced mixing. At the same time, high freestream turbulence also produces a 50-100% increase in film cooling effectiveness in the region between injection holds. This is due to accelerated spanwise diffusion of the cooling fluid, which also produces an earlier merger of the coolant jets from adjacent holes.

Download or read book Effect of High Free Stream Turbulence on Film Cooling Using Double Row of 30 Deg Slant Hole Injectors written by Lilith I. Sorensen and published by . This book was released on 1998-03-01 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this study free stream turbulence levels from 7.3% to 17.8% are applied to film cooling over a flat plate with two rows of 30 deg slant holes using a wall jet as the main stream air supply and source of turbulence. Blowing ratios are varied from 0.25 to 2.0 and free stream velocities at injection range from 10 m/s to 85 m/s. A constant density ratio of 1.07 is kept throughout the experiment. Results show that for different magnitudes of blowing ratio free stream turbulence has a different influence on effectiveness. At the forward stations, where blow off was present at high blowing ratios, high free stream turbulence increased effectiveness. While at mid to aft stations for all blowing ratios high free stream turbulence decreased effectiveness. A correlation for effectiveness with a non-dimensional group of film cooling parameters is offered. The effectiveness correlated best 10 to 15 diameters after injection where blow off effects are no longer present, and before the very far downstream stations where uncertainties in the measurements were greater.

Download or read book Effect of High Free Stream Turbulence on Film Cooling Using Double Row of 30 Degree Slant hole Injectors written by Lilith I. Sorensen and published by . This book was released on 1998 with total page 200 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ninety Degree Skew Leading Edge Film Cooling Effectiveness Heat Transfer and Discharge Coefficients for Cylindrical Film Holes at High Free Stream Turbulence written by and published by . This book was released on 2003 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This paper studies the film effectiveness and heat transfer coefficients on a large scale symmetric circular leading edge with three rows of film holes. The film hole configuration focuses on a smaller injection angle of 20 deg and a larger hole pitch with respect to the hole diameter (P/d=7.86). The study includes four blowing ratios (M=1.0, 1.5, 2.0 and 2.5), two Reynolds numbers (Re-30,000 and 60,000), and two free stream turbulence levels (approximately Tu=1% and 20% depending on the Reynolds number). The measured discharge coefficients of the film holes were 0.62-0.69 and 0.39 -0.54 at the stagnation row and 0.54-0.59 and 0.47-0.52 at 21.5 deg the row, for the range of blowing ratios investigated and Re's of 60,000 and 30,000 respectively. A transient liquid crystal technique was used to obtain the film cooling effectiveness and the heat transfer coefficients. The distributions of film effectiveness and heat transfer coefficient are obtained with spatial resolutions of 0.6mm or 13% of the film cooling hole diameter. Results are presented for detailed and spanwise averaged values of film effectiveness and Frossling number. Blowing ratios investigated result in up to 2.8 times the lowest blowing ratio's film effectiveness. Increasing the Reynolds number from 30,000 to 60,000 results in increasing the effectiveness by up to 55% at high (20%)turbulence. Turbulence intensity has up to a 60% attenuation on effectiveness between rows at Re=30,000. The turbulence intensity has the same order of magnitude but opposite effect as Reynolds number, which also has the same order of magnitude effect as blowing ratio on the film effectiveness. A crossover from attenuation to improved film effectiveness after the second row of film holes is found for the high turbulence case as blowing ratio increases. The blowing ratio of two shows a spatial coupling of the stagnation row of film holes with the second row (2.15 deg) of film holes, which results in the highest Frossling num7.

Download or read book Full coverage Film Cooling written by S. Yavuzkurt and published by . This book was released on 1979 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Film Cooling with Forward and Backward Injection for Cylindrical and Fan shaped Holes Using PSP Measurement Technique written by Andrew F. Chen and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A systematic study was performed to investigate the combined effects of hole geometry, blowing ratio, density ratio and free-stream turbulence intensity on flat plate film cooling with forward and backward injection. Detailed film cooling effectiveness distributions were obtained using the steady state pressure sensitive paint (PSP) technique. Four common film-hole geometries with forward injection were used in this study: simple angled cylindrical holes and fan-shaped holes, and compound angled (ß= 45°) cylindrical holes and fan-shaped holes. Additional four film-hole geometries with backward injection were tested by reversing the injection direction from forward to backward to the mainstream. There are seven holes in a row on each plate and each hole is 4 mm in diameter. The blowing ratio effect is studied at 10 different blowing ratios ranging from M = 0.3 to M = 2.0. The coolant to main stream density ratio (DR) effect is studied by using foreign gases with DR = 1 (N2), 1.5 (CO2), and 2 (15% SF6 + 85% Ar). The free stream turbulence intensity effect is tested at 0.5% and 6%. The results of the parametric effects to the film cooling effectiveness with forward injection agreed with open literatures. In general, the results show the film cooling effectiveness with backward injection is greatly reduced for shaped holes as compared with the forward injection. However, significant improvements can be seen in simple angled cylindrical hole at higher blowing ratios. Backward injection also shows improvements at near film-hole regions for compound angled cylindrical holes at higher blowing ratios. Comparison was made between the experimental data and empirical correlation for simple angled fan-shaped holes. The electronic version of this dissertation is accessible from http://hdl.handle.net/1969.1/151849

Download or read book Effects of Hole Length Supply Plenum Geometry and Freestream Turbulence on Film Cooling Performance written by and published by . This book was released on 2000 with total page 324 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book An Experimental Investigation of the Effect of Freestream Turbulence on Film Cooling Using Thermochromic Liquid Crystal Thermography written by James Edward Mayhew and published by . This book was released on 1999 with total page 482 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Measurement of Film Cooling Effectiveness on a Flat Plate Following a Row of Inclined Injection Tubes written by Sassan Roham and published by . This book was released on 1990 with total page 110 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Film Cooling Effectiveness and Heat Transfer with Injection Through Holes written by Vernon Lee Eriksen and published by . This book was released on 1971 with total page 362 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Film Cooling on a Flat Plate written by Joshua Peter Fletcher Grizzle and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This study is an investigation of two specific effects on turbine blade film cooling. The effect of coolant to mainstream density ratio and upstream steps was studied. The studies were conducted on two flat plates with 4mm cylindrical film cooling holes, one with simple angle and the other with compound angle, in a low-speed suction type wind tunnel. Density effect was studied at ratios of 0.93 and 1.47 by using air and CO2 as coolant. An IR camera was used to record the temperature on the plate and T-type thermocouples were used to record the coolant and mainstream temperatures. During the study the nature of the conduction effect from the heated coolant was studied and found to be most prevalent along the plate surface not through the plate from the plenum. A methodology was presented by which conduction error free results were obtained. The results showed an increased effectiveness at higher density ratios, particularly near the holes and for the simple angle plate. Upstream step effect was studied using pressure sensitive paint and a coupled strobe light and camera. Steps of 0.5, 1 and 1.5mm were placed at the upstream edge of the holes. The steps were found to increase effectiveness significantly more than previous studies have shown when placing the step slightly upstream of the holes.

Download or read book Effect on Gaseous Film Cooling of Coolant Injection Through Angled Slots and Normal Holes written by S. Stephen Papell and published by . This book was released on 1960 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Film Cooling Effectiveness Downstream of a Single Row of Holes with Variable Density Ratio written by A. K. Sinha and published by . This book was released on 1990 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Film-cooling effectiveness was studied using a row of inclined holes that injected cryogenically cooled air across a flat, adiabatic test plate. The density ratio of the coolant to mainstream varied from 1.2 to 2.0. Surface temperatures were measured using a unique surface thermocouple arrangement free of conduction errors. Temperatures were obtained along the jet centerline and across a number of lateral locations. By independently varying density ratio and blowing rate, scaling of adiabatic effectiveness with mass flux ratio, velocity ratio, and momentum ratio was determined. Depending on the momentum flux ratio, the jet either remains attached to the surface, detaches and then reattaches, or is fully detached. For attached jets, the centerline effectiveness scaled with the mass flux ratio. However, for detached-reattached jets, a consistent scaling was not found although the general distribution of the centerline effectiveness scaled with momentum flux ratio. Laterally averaged effectiveness was found to be dependent on density ratio and momentum flux ratio. Decreases in density ratio and increases in momentum flux ratio were found to reduce the spreading of the film cooling jet significantly and thereby reduce laterally averaged effectiveness.

Download or read book Effects of Hole Length Supply Plenum Geometry and Freestream Turbulence on Film Cooling Performance written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-27 with total page 322 pages. Available in PDF, EPUB and Kindle. Book excerpt: Experimental measurements are presented in this report to document the sensitivity of film cooling performance to the hole length and coolant delivery plenum geometry. Measurements with hot-wire anemometry detail velocity, local turbulence, and spectral distributions over the exit plane of film cooling holes and downstream of injection in the coolant-freestream interaction zone. Measurements of discharge coefficients and adiabatic effectiveness are also provided. Coolant is supplied to the film cooling holes by means of a large, open plenum and through plenums which force the coolant to approach the holes either co-current or counter-current to the freestream. A single row of film cooling holes with 35 degree-inclined streamwise at two coolant-to-freestream velocity ratios, 0.5 and 1.0, is investigated. The coolant-to-freestream density ratio is maintained in the range 0.96 to 1.0. Measurements were taken under high-freestream (FSTI = 12%) and low-freestream turbulence intensity (FSTI = 0.5%) conditions. The results document the effects of the hole L/D, coolant supply plenum geometry, velocity ratio, and FSTI. In general, hole L/D and the supply plenum geometry play influential roles in the film cooling performance. Hole L/D effects, however, are more pronounced. Film cooling performance is also dependent upon the velocity ratio and FSTI. Burd, Steven W. and Simon, Terrence W. and Thurman, Douglas (Technical Monitor) Glenn Research Center NAG3-1638; RTOP 714-01-4A...

Download or read book Effect of High Mainstream Turbulence on Leading Edge Heat Transfer and Film Cooling written by Anant Bhaskar Mehendale and published by . This book was released on 1991 with total page 622 pages. Available in PDF, EPUB and Kindle. Book excerpt: